Interplay between early rifting and sedimentary filling along 250 Myr of a long-lived Tethys remnant: the Levant Basin

Rifted margins include the Earth’s most voluminous sediment accumulation, host important energy and natural resources providing a rich archive for global environmental changes. However, revealing the deep structure within rifted basins is challenging, because their deep part is commonly vogue in seismic images and their structure is complex because it is usually affected by several deformation phases that occurred during their long history. The Levant Basin is a good example for a deep Tethyan basin that formed alongside Gondwana breakup. Unlike many Tethyan basins that were eroded and/or severely deformed during the Alpine orogeny, the Levant Basin has preserved a thick (>15 km), long-lived (>250 Myr), and continuous sedimentary record providing a world-class archive to study the role of post-rift subsidence and sediment supply on depocenter evolution.

We synthesize regional seismic interpretations from previous studies utilizing thousands of kilometers of seismic lines and tens of wells in a unified dataset. By applying a low pass post-stack filtering on 2D seismic reflection surveys covering the Israeli economic water, we improved the imaging of the deeper reflectors and enabled the distinction of the deep units, which otherwise appeared blurred at conventional industry processed data. Based on thickness analysis, we identify the syn-rift to post rift transition. The regional seismic horizon marking this transition is tied to dated horizons in wells providing a concrete age constraint of pre- 163 Ma (end of Callovian) for the end of rifting, which was previously debated. In addition, we show that rifting comprises at least two phases, which are equivalent to three extensional phases documented onshore: Permian, Mid-Late Triassic and Early-Mid Jurassic.

Analysis of 11-thickness maps showcase the 250 Myr evolution of sedimentary filling, opening a discussion about the parameters that controlled depocenter migration in relation to tectonic subsidence and sediment supply. We distinguish between periods during which near margin accumulation dominated versus periods during which more sediments accumulated in the deep basin. We explain these variations in light of sediment sources in surrounding continents and paths of transport. Marginal accumulation periods (syn-rift, early post-rift, and Pliocene-Quaternary) represents dominance of shallow biogenic and nearby terrestrial (silisiclastic) sources, whereas, deep basin accumulation periods represent sediment supply that was either provided from the water column (pelagic micro- and nano-fossils, Santonian to Mid-Eocene), or transported mostly from Africa with minimal accumulation along the Levant margin (during the Late-Eocene to Miocene).